Solar Panels

[manesty]

Hi

We purchased a newish Taylor Wimpy house that has an on grid solar power system installed.

  The house is approx. 4.5 years old, and we purchased it approx. 2.5 years ago

The problem is the original owners did not register the system (this has to be completed within the first year). So we now have a grid system, but are not receiving any FIT.

To get any benefits out of the system would it be possible to disconnect the PV system for the grid, and use the power generated by the solar system to run the hot water emersion heater.

 

[roys]

Without seeing the system, I would presume that the house uses the electricity that the solar panels generate and only the surplus is sent to grid. So if your house is using say 1kW and you are generating 1.5kW then you will only be exporting 0.5kW to the grid and you will be getting free electric for your house load.

You can utilise this exported power by getting a solar diverter installed and divert it to say an immersion heater if you have a hot water cylinder.

You would have to work out it this would be worthwhile taking into account the price and install cost of a solar diverter V the amount of electricity you actually export.

 

[binky]

OK, that wasn't unusual for new builds, and you won't be losing much FiT anyway as the rate was so low. Do not attempt to disconnect from the grid as the inverter will not work without a grid connection. What you can do is register for the Export Guarantee scheme in January, which will pay you for energy exported at about 5p per kWh, but the best thing you can do is fit a Solic 200 immersion controller, this will direct any spare energy to your immersion, so you get free / cheaper hot water. Any energy used is worth around 16p . The Solic is best wired in parallel to any immersion controls you have, this will allow your current timer to guarantee hot water - set any timer not to heat water say after 7am, so that any solar energy can be directed to a cold / part cold tank of water during daylight hours to absorb it. 

 

[roys]

@binky What size of system did they tend to fit on these new builds?

 

[ProDave]

Also, if you are home in the daytime, do all your washing, tumble drying, dishwashing etc one machine at a time in the daytime. If you are out, set them on a timer to come on in the day.

I recon I am on course to self use about £250 worth of electricity each year.

The export scheme @binky mentions will require you to have a smart meter fitted and you will need the MCS paperwork (if it exists) from the original install.

 

[Murdoch]

I recon I am on course to self use about £250 worth of electricity each year.

I hope you don't mind me asking but how long is the ROI on your system?

 

[ProDave]

I hope you don't mind me asking but how long is the ROI on your system?

6 years I estimate.  I had to work VERY hard and search far and wide to get it that cheap.

 

[binky]

@binky What size of system did they tend to fit on these new builds?

 bugger all! 1 or 1.5 kWp

 

[ProDave]

 bugger all! 1 or 1.5 kWp

Typical of mass market house builders, they probably only fitted them to get a few more SAP points to scrape a pass through building regs. They are not the least bit interested in building good houses, just houses that scrape through building regs as cheap as possible.

 

[Murdoch]

6 years I estimate.  I had to work VERY hard and search far and wide to get it that cheap.

That's very impressive - did you flat line the cost of lecky over the 6 years or add price increases per year

So not only are you saving money, its you doing your bit for the planet too

 

[ProDave]

That's very impressive - did you flat line the cost of lecky over the 6 years or add price increases per year

So not only are you saving money, its you doing your bit for the planet too

That assumes electricty stays as it is today. If electricity goes up my 6 year payback could shorten.

Yes I am "doing my bit".  My new build is virtually to passive house standards (though not certified as such) Very well insulated and air tight. Heated with an air source heat pump and the solar panels help to reduce the electricity bill somewhat.  So far since the PV going live in January, I have only exported 105Kwh the rest has been self used.  Even if I qualified for this new export payment scheme (which I don't) I would have received less than £6 so far.

Last winters heating bill was £234. There is scope for that to come down as there are a couple of details of the house not finished that will be allowing some heat loss.

If I don't get an EPC A when it's finished I will be disappointed.

What annoys me is it is not particularly expensive to build properly, but very few seem bothered to try and make something better than the average mass built leaky box.

 

[Murdoch]

That assumes electricity stays as it is today. If electricity goes up my 6 year payback could shorten.

I can't imagine it getting cheaper. 

I've wondered about installing PV ............ ATM with 4 "adults" in the house we are using over 5000 KWH per year - so there has to be some savings to be had - but at what cost? I did run in a cable from the loft to the fuseboard.

As for the heating costs, when we refurbished the house, (its a 1980's house), there is more insulation, but its difficult to do more than turn the heating down and put on a thicker jumper - then the missues turns up the heat!

 

[ProDave]

Insulation is part of the energy saving and the most obvious bit. We have a lot of insulation and decent quality triple glazed windows and doors.

The next thing is air tightness. Our house is sealed with an air tight membrane covering the whole of the inside and the windows don't have vents.  Instead we have an MVHR system (mechanical ventilation with heat recovery)  That extracts otherwise wasted heat from the exhausted air and puts most of that heat back into the fresh air coming in.

The air tightness thing would be very hard to get right on a refurb, it really has to be thought of at build time.  And as I say the silly part is that does not cost much, it is mostly attention to detail rather than anything hugely expensive.

 

[binky]

Typical of mass market house builders, they probably only fitted them to get a few more SAP points to scrape a pass through building regs. They are not the least bit interested in building good houses, just houses that scrape through building regs as cheap as possible.

precisely, it's rediculous, it wouldn't cost that much more to install a 3/4 kw system, but...

 

[binky]

I've wondered about installing PV ............ ATM with 4 "adults" in the house we are using over 5000 KWH per year - so there has to be some savings to be had - but at what cost? I did run in a cable from the loft to the fuseboard.

with tat sort of leccy use it is worth considering . Nothing to stop you doing it yourself, you only have to motify the DNO. A kit of arts, new, not second hand stuff that ProDave bought comes in around £2,500 inc VAT, assuming you use about half the leccy that would be a saving of about £400 per year. Factor in scaffolding and help of a roofer say £3,500 / £4,000 total. 

 

[Murdoch]

with tat sort of leccy use it is worth considering . Nothing to stop you doing it yourself, you only have to motify the DNO. A kit of arts, new, not second hand stuff that ProDave bought comes in around £2,500 inc VAT, assuming you use about half the leccy that would be a saving of about £400 per year. Factor in scaffolding and help of a roofer say £3,500 / £4,000 total. 

Nice one. Thanks.

our roof is facing almost due south with absolutely no shading .....

 

[binky]

will work a treat then. Lets be honest leccy isn't going to get cheaper - the Chinese will be drainng money out of Hinckley point.

 

[roys]

Aww Murdoch get it fitted, I got my system fitted in 2012, no regrets, mine is FIT registered and had to be fitted by a MCS installer, however since then the inverter has been changed and at the start of this year I took all the panels of my roof, got a roofer to retire it (tiles and battens 55 years old and done) and once it was done I put all the panels back on, on a Sunday morning. Think I had my panels of for a year.

If I was to move house and I had a suitable roof I wouldn’t hesitate to fit a system myself as the MCS registered installer for FIT payment is dead. As Dave says all you have to do is inform the DNO (below 4kW ish I believe).

 

[binky]

the limit is 16A, which is roughly 3.68kW inverter. Up to 16A your DNO can't stop you, over 16A they can tell you to turn it off. Now a 16A limited inverter can take more panels than that, some as high as nearly 5kW, although that# not worth ding unless you have a split array.  Not sure what insurance companies will make of diy solar panels? 

 

[Murdoch]

the limit is 16A, which is roughly 3.68kW inverter. Up to 16A your DNO can't stop you, over 16A they can tell you to turn it off. Now a 16A limited inverter can take more panels than that, some as high as nearly 5kW, although that# not worth ding unless you have a split array.  Not sure what insurance companies will make of diy solar panels? 

Re the 16A limit ........ how would they know its more than that?

I can see online suppliers selling DIY kits for around £4K ....... mind you, I'm not going on the roof!